Krebs on Security

In-depth security news and investigation

Posts Tagged: MessageLabs

Last week, National Public Radio aired a story on my Pharma Wars series, which chronicles an epic battle between men who ran two competing cybercrime empires that used spam to pimp online pharmacy sites. As I was working with the NPR reporter on the story, I was struck by how much spam has decreased over the past couple of years.

Below is a graphic that’s based on spam data collected by Symantec‘s MessageLabs. It shows that global spam volumes fell and spiked fairly regularly, from highs of 6 trillion messages sent per month to just below 1 trillion. I produced this graph based on Symantec’s raw spam data.

Some of the points on the graph where spam volumes fall precipitously roughly coincide with major disruptive events, such as the disconnection of rogue ISPs McColo Corp. and 3FN, as well as targeted takedowns against major spam botnets, including Bredolab, Rustock and Grum. Obviously, this graph shows a correlation to those events, not a direct causation; there may well have been other events other than those mentioned that caused decreases in junk email volumes worldwide. Nevertheless, it is clear that the closure of the SpamIt affiliate program in the fall of 2010 marked the beginning of a steep and steady decline of spam volumes that persists to this day.

Of course, spam volumes are relative, depending on where you live and which providers you rely on for email and connections to the larger Internet. As I was putting together these charts, I also asked for spam data from Cloudmark, a San Francisco-based email security firm. Their data (shown in the graphs below) paint a very interesting picture of the difference in percentage of email that is spam coming from users of the top three email services: The spam percentages were Yahoo! (22%), Microsoft (11%) and Google (6%).

Global spam volumes have fallen precipitously in the past two months, thanks largely to the cessation of junk e-mail from Rustock – until recently the world’s most active spam botnet. But experts say the hackers behind Rustock have since shifted the botnet’s resources toward other money-making activities, such as installing spyware and adware.

The decline in spam began in early October, shortly after the closure of Spamit, a Russian affiliate program that paid junk e-mail purveyors to promote Canadian Pharmacy brand pill sites. The graphic below, from M86 Security Labs, shows a sharp drop in overall spam levels from October through the end of 2010.

Another graphic from M86 shows that spam from Rustock positively tanked after Spamit’s closure. Rustock is indicated by the pale blue line near the top of the graphic.

Prior to the Spamit closure, Rustock was responsible for sending a huge percentage of all spam worldwide, M86 reported. But since Christmas Day, the Rustock botnet has basically disappeared, as the amount of junk messages from it has fallen below 0.5 percent of all spam, according to researchers at Symantec‘s anti-spam unit MessageLabs.